Mattress



FIG. 1 is a front, right side, top perspective view of a mattress showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is an enlarged view of the encircled region 8 shown in FIG. 1;

FIG. 9 is an enlarged view of the encircled region 9 shown in FIG. 2; and,

FIG. 10 is an enlarged view of the encircled region 10 shown in FIG. 7. 

CLAIM The ornamental design for a mattress, as shown and described. 